# pair_style smd/tlsph command

## Syntax

``` LAMMPS
pair_style smd/tlsph args
```

## Examples

``` LAMMPS
pair_style smd/tlsph
```

## Description

The *smd/tlsph* style computes particle interactions according to
continuum mechanics constitutive laws and a Total-Lagrangian
Smooth-Particle Hydrodynamics algorithm.

This pair style is invoked with the following command:

``` LAMMPS
pair_style smd/tlsph
pair_coeff i j *COMMON rho0 E nu Q1 Q2 hg Cp &
               *END
```

Here, *i* and *j* denote the *LAMMPS* particle types for which this pair
style is defined. Note that *i* and *j* must be equal, i.e., no *tlsph*
cross interactions between different particle types are allowed. In
contrast to the usual *LAMMPS* *pair coeff* definitions, which are given
solely a number of floats and integers, the *tlsph* *pair coeff*
definition is organized using keywords. These keywords mark the
beginning of different sets of parameters for particle properties,
material constitutive models, and damage models. The *pair coeff* line
must be terminated with the *\*END* keyword. The use the line
continuation operator *&* is recommended. A typical invocation of the
*tlsph* for a solid body would consist of an equation of state for
computing the pressure (the diagonal components of the stress tensor),
and a material model to compute shear stresses (the off-diagonal
components of the stress tensor). Damage and failure models can also be
added.

Please see the [SMD user guide](PDF/MACHDYN_LAMMPS_userguide.pdf)\_ for
a complete listing of the possible keywords and material models.

------------------------------------------------------------------------

## Mixing, shift, table, tail correction, restart, rRESPA info

No mixing is performed automatically. Currently, no part of MACHDYN
supports restarting nor minimization. rRESPA does not apply to this pair
style.

------------------------------------------------------------------------

## Restrictions

This fix is part of the MACHDYN package. It is only enabled if LAMMPS
was built with that package. See the [Build package](Build_package) page
for more info.

## Related commands

[pair_coeff](pair_coeff)

## Default

none